The best DIY canister filter I seen is the one I build back in 1998
Using plastics glass. Don't have any pic of the filter but I still have the design of the filter in those big floppy disk. Lol

Thanks!

Here's the progress for today:

The inflow and outflow pipes are just cemented in with Weld-on #16 (I'm all out of #4).

For the pump cord, I cut a 1/4" long section of 1/2" ID acrylic tube, glued a flat bottom on it and glued all of that under a 3/8" hole in the lid. Then I drilled a hole the size of the cord in the little flat bottom, and pulled the cord through. This left a "well" where the cord passed through the lid which I filled with Weld-on. Hopefully that 1/2" long plug of new acrylic will seal around the cord. I'm letting all of the weld-on set for 24 hours before testing anything.